Canine seizure basics

So for the first monthly report of seizure updates I thought I would go “back to basics” with regard to canine epilepsy and particularly psychomotor seizures.

First thing to understand is that epilepsy is a neurological disease. It is like an electrical firestorm in the brain. Seizures are the consequence of that electrical firestorm. However, those electrical firestorms can occur from epilepsy, brain tumors, encephalitis, infection, head trauma, stroke, Alzheimer’s, and many other sources. Epilepsy happens to be the disease of repetition of seizures.

There is primary or secondary epilepsy. Primary epilepsy is essentially a diagnosis of exclusion. This is also referred to as genetic or idiopathic epilepsy. This is Reggie’s diagnosis (idiopathic epilepsy). It presents between the ages of 1-5 (Reggie was 3) and has no known reason or cause. Secondary epilepsy is a diagnosis for which there is a reason. For instance hypothyroidism, kidney or liver damage, or a brain tumor.

The most common types of seizures are grand mal and partial seizures.  Grand mal seizures are recognizable; your dog falls, stiffens as the muscles contract and spasm, there is a loss of consciousness, there can be chewing motions, paddling of the limbs, pupillary dilation, respiratory distress, and loss of bowel and bladder control. Partial seizures affect only a partial area of the body; a jerking or twitching of the head say, or the trunk, facial twitches, etc.

Rare types of seizures are petite mal (also called absence) seizures, and complex partial (formerly called psychomotor or behavioral) seizures. In humans, petite mal seizures are marked by brief periods of unconsciousness, blank stares, and looking skyward. Depending on the source, some articles indicate that petite mal seizures do not occur in dogs, or is a term misused by vets because it is actually a different disorder. Complex partial seizures is what Reggie has (the new terminology) and these are complex behaviors or actions that are repeated during a seizure episode. Depending on the area of the brain affected, the behavior or action can  be very different. For instance, humans can experience distortion of thought, emotion, perception (like fear, deja vu or jamais vu) and this can be accompanied by visual, auditory or olfactory sensations. While there is a lack of awareness, almost an amnesiac state, there is not usually a lack of consciousness. Translate this to a canine world and symptoms are fly-biting, lip smacking, pupillary dilation (temporary blindness or blurred vision), howling, whining, running, cowering, hiding, loss of bowel or bladder control, and sometimes aggression.

Cluster seizures or status epilepticus are both very serious situations that require emergency medical attention. Cluster seizures are multiple seizures occurring within a short time frame. Status epilepticus is essentially the same, with two tweaks. One seizure lasting 30 minutes or longer or multiple seizures in a short time frame without regaining consciousness. Reggie’s vet has a rule: no more than three seizures in one hour, then you are at a cluster threshold. When Reggie first presented he had 14 seizures in a little more than 12 hours. He has had one other cluster seizure episode. He had six seizures in about two hours- the time it took me to assess is he going to have another? and then call the ER and get him up there. The vets have to break that seizure cycle and determine if medications need to be adjusted.

There is a term called the “seizure threshold”. If your dog has a low seizure threshold, he is susceptible to triggers- missed or late meds, heat, certain foods, etc. that can potentially trigger a seizure. If your dog has a high seizure threshold, he can withstand more of these things than a low threshold dog can. Studies show that dogs with idiopathic epilepsy (like Reggie) have a distinctly low threshold.

Repetitive uncontrolled seizures can lower that threshold. Remember that electrical firestorm? The epileptic neurons in the brain recruit normal neurons back to epilepsy base camp, thereby enlarging the area of the brain that produces seizures. This larger base camp now has increased excitability (that firestorm) and increased ability to cause seizures, regardless of outside triggers. There is also a “mirror” phenomenon in the brain. Let’s say the seizures are occurring in a specific area in the left hemisphere of your dog’s brain. In an EEG, the abnormal brain wave patterns would show up. In a matter of weeks the right hemisphere will start to show similar brain wave abnormalities and would be capable of causing seizure activity on its own.

The seizure itself. There is the prodome (which can include the aura or be a separate stage), the seizure, and the post-ichtal stage. The prodome stage can last for hours or sometimes days. It can include mood changes, lethargy, and behavioral changes. Reggie will act very clingy and follow me around. I think he has that feeling that something is coming and he is scared, unsure, and follows me around for comfort. Once when we were walking we met two huskies and when the dogs met each other the huskies whimpered and backed away from Reggie. Reggie just stood there, unreactive. Later that night he had a seizure. Dogs know stuff. Most seizures occur when the brain is shifting into sleep/wake cycles. In other words, in the morning, at night, or during sleep. During the seizure keep your dog safe. Keep your dog away from stairs and pools. The post-ichtal phase can leave your dog disoriented, confused, the temporary blindness may not have worn off, and sleepy. Your dog is conscious but not really functioning- don’t go running. Reggie sleeps for several hours after a seizure.

Keep a seizure journal and call your vet every time your dog has a seizure. Note what works and what doesn’t- Reggie is comforted by my presence but I do not need to use my voice or my touch. I learned the very first time he can exhibit aggression if he is touched at all during a seizure, and really there is no reason to touch a seizing dog unless I need to grab him away from the stairs. Keep straight with your medications, never change dosages, skip doses, or stop without consent or knowledge of your vet. Reggie takes two separate meds four times a day, and yes it’s a burden on your schedule sometimes, but his health and longevity are far more important.

I will never forget the day that Reggie started having seizures at a friend’s house. I think this friend is scarred now because once you see this type of seizure you will never forget it. Epilepsy is a manageable disease. It seems daunting and terrifying but you can handle it!

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